1. Field of the Invention
The invention relates generally to optoelectronic devices and means for optically coupling thereto.
More particularly the invention relates to a low profile silhouette package of an optoelectronic device and an associated optical coupler.
Even more specifically the invention relates to a planar substrate having an optoelectronic device mounted generally planar thereto in a module package to which an optical light fiber is introduced on a line essentially parallel with said planar substrate.
1. Prior Art
An optoelectronic device is an electronic device combining both optic and electric ports. Hereinafter, the optoelectronic device will be referred to as an "op-el" device. An op-el device may be either a light receiver, such as a photodiode, or a light transmitter, such as a light emitting diode (LED). The op-el device may be formed of op-el cells as part of an integrated circuit device or it may be a discrete component on a hybrid circuit device.
In general, the prior art provides two methods for providing light coupling to an op-el module. In the first of these, the op-el device is generally planar with the substrate of the associated circuitry. Where the planar situs is employed, conventional production techniques may be utilized to provide the necessary electric connections to the electric ports of the op-el device. Light coupling means, most frequently in the form of light conducting fibers, are introduced to the op-el package at an angle substantially normal to the substrate plane in which the op-el device lies. The light fiber is supported in an optical fiber connector and the overall assembly of optical connector and module package is somewhat reminiscent of the outline of a single story factory building having a tall smokestack rising upwards from its roof structure.
To reduce the profile of the silhouette of the op-el device package, a second approach to introducing optical coupling is employed. With this alternate approach, the op-el device is a discrete component mounted on a dielectric standoff above the substrate of the associated circuitry such that the plane of the optic ports of the op-el device is generally perpendicular to the plane of the substrate. This configuration has distinct disadvantages in that standard production techniques for making connection to the electric ports of the op-el device can no longer be utilized. Special manufacturing procedures must be devised and used to successfully produce a module of this type. However, this configuration permits the optical connector to introduce the optical fiber on a plane essentially parallel with the plane of the substrate, thus somewhat increasing the length of the package while still maintaining its low profile silhouette.
Prior art which relates to photodetector packaging and optical coupling systems may be found in U.S. Pat. Nos. 3,757,127; 4,112,308; and 4,136,357. None of this known prior art discloses apparatus or methods for maintaining a low package silhouette when optically coupling to an op-el device package while maintaining the op-el device essentially planar with the substrate of the associated circuitry.
Accordingly it is an object of the present invention to provide an op-el module utilizing fiber optics to provide light coupling, which module shall present a low profile silhouette.
It is a further object of the invention to provide a low profile silhouette package utilizing optical fiber, light coupling to an op-el device, which op-el device is essentially planar with the substrate of the associated circuitry within the package.
it is a more specific objective of the invention to provide fiber optic light coupling through an op-el device in such a manner that the optical fiber performs a secondary function in simplifying the manufacturing and assembly of the fiber optic/op-el device module.